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FERNSEH · 28th Apr 2017, 11:58 am

Some progress with the HMV 1804. A suitable frame blocking oscillator transformer has been found to replace the Pye type transformer with three windings, that component is now fitted in my Pye D16T. The replacement transformer was removed from a scrap Ekco TMB272 and in order that it would fit in the HMV an adaptor plate has been made for it. The frame oscillator and output stage have been isolated from the rest of the circuit and supplied from a separate power source, and it works, there's a 50volt P - P sawtooth waveform present at the anode of the KTZ63 oscillator valve. The waveforms present at the anode of the KT61 output valve are bit strange though.
So later today I'll turn my attention to the line timebase blocking oscillator.

DFWB.

28th Apr 2017, 11:58 am	#28
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: HMV 1804 Television. Some progress with the HMV 1804. A suitable frame blocking oscillator transformer has been found to replace the Pye type transformer with three windings, that component is now fitted in my Pye D16T. The replacement transformer was removed from a scrap Ekco TMB272 and in order that it would fit in the HMV an adaptor plate has been made for it. The frame oscillator and output stage have been isolated from the rest of the circuit and supplied from a separate power source, and it works, there's a 50volt P - P sawtooth waveform present at the anode of the KTZ63 oscillator valve. The waveforms present at the anode of the KT61 output valve are bit strange though. So later today I'll turn my attention to the line timebase blocking oscillator. DFWB.